Thermostat.



M. M. MASON.

THERMOSTAT APPLICATION mm JUNE H. 1914.

Patented Nov. 6, 1917.

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MERLE M. MASON, OF CLEVELAND, OHIO.

THERMOS'IAT.

Specification of Letters Patent.

Patented Nov. 6, 1917.

Application filed June 11, 1914. Serial No. 844,581.

To all whom it may concern:

Be it known that I, MERLE M. MASON, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certain new and useful Improvement in Thermostats, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

This invention is for a theromostat adapted to be used in connection with a system for regulating temperature. The object of this invention is to provide a device of the character described which will be simple in construction, easily manufactured and accurate and durable in use.

A feature of my invention is that the main body of the mechanism, electric contacts, etc., are so constructed that the thermostat may be utilized without bringing these delicate parts into contact with extreme temperatures. Another feature of my invention is that it provides adjustment for a wide range of temperature.

Another object is to provide contacts which may be readily shifted independently of each other to provide for use under a great variety of conditions.

My invention is hereinafter more fully described in connection with the drawings and the essential characteristics are set forth in the claims.

In the drawings, Figure 1 is a rear elevation of my device with the back cover removed, showing the thermostatic elements extending into a container; Fig. 2 is a vertical central section through my device; Fig. 3 is a fragmentary section on the lines 33 of Fig. 2; Fig. 4 is a fragmentary section on the line 4--4 of Fig. 2.

Referring to the parts by numeral, the device is shown inclosed in a suitable casing 10 having a removable back portion 11 with a panel of insulating material 12 rigidly carried thereby, provided with a dial face 13 of suitable non-inflammable material which may he graduated by calibration, or otherwise. An opening 1 1 is provided in the front cover of the casing to allow an observation of the graduations before men tioned, and which may be closed by means of glass or mica or other'suitable material, if desired. Rigidly connected to the base of the case are shown legs 15 adapted to be supported by the walls of a container shown at 16 into which the thermostat is adapted to extend through an opening, as at 17 The thermostat elements preferably comprise a thin tube 20 of some material having a high co-efiicienoy of expansion, being sealed at its lower end as at 21, and rigidly connected at its upper end to a bushing 22, by means of screws 23, which in turn is adapted to be rigidly connected to the base of the case 10. Secured to the interior of the tube 20, near its lower end, is provided a flanged bushing 25 adapted to inclose and support a collar 26, of some material of low conductivity. A rod 30 of some material having a low co-efliciency of expansion, passes through the collar and is riveted over to form a head, as at 31, adapted to bear against the collar and thereby prevent an upward movement of this end of the rod 30. This rod 30 passes upwardly through a tube 29, of asbestos or other material of low conductivity, which is adapted to insulate the rod 30 from the tube 20 in which it is contained. The upper end of the rod 30 passes through the bushing 22, being insulated therefrom by means of a similar asbestos tube 24, and passes through a slot 3a in a multiplying lever 35, hereinafter described, and loosely through a suitable hole in the body of a knife edge 36, being threaded at its upper end and provided with a suitable nut 37 adapted to bear againstthe upper face of the knife edge 36.

As the tube 20 is heated, being of material having a high co-efliciency of expansion, it will elongate much more rapidly than the rod 30, which is, however, insulated to prevent even a slight increase in its length due to a rise in temperature in the container. The downward movement of the end of the rod 20, transmitted through the bushing 25 and the collar 26, pulls downwardly on the rod 30, which in turn pulls downwardly on the knife edge 36. This knife edge is adapted to rest in the grooves formed on the upper edge of a multiplying lever 35 on either side of the slot 34, and so tends to depress this end of the lever. The lever 35 is pivoted in a case formed of two plates 40 and 41 spaced apart by suitable washers and adapted to be clamped through the washers to a plate of insulating material 42 hereinafter described, by means of suitable screws 43. As shown, this pivot is formed of a knife edge 38 rigidly connected to the lever 35 and carried in grooves formed on the lower edge of openings 46 and 47 in the plates 40 and 41 respectively.

The upper end of an indicator 50 lies in a plane in front of the dial 13 and is bent rearwardly beneath the dial to a plane back of the plate 40, then downwardly, being rigidly connected to a pivot 51, mounted in the plate 41 at the center near the upper edge and in a bracket 44 rigidly connected to the plate 40, which is cut away as at 45 to provide a clearance for the pivot. The indicator extends below the pivot, having at its lower end a suitable counterweight 52 adapted to return the indicator to its normal position. liigidly connected to the pivot 51 in a plane between the plates 40 and 41, is provided a pinion 53 adapted to mesh with a gear segment 54 pivoted at 55, having an outstanding arm provided with a knife edge 56, adapted to bear against a shoulder 57 formed on the lever'35, on the opposite end from the knife edge 36. At the other end of the lever 35, I have provided a spring 58 connected to the lever and supported at its upper end by means of a pin 59 extending through the plates 40 and 41.

It will be seen that a downward move ment of the rod 30, hereinbefore described as caused by heating the tube 20, will depress the righthand end of the lever 35 against the action of the spring 58 and, being pivoted by the knife edge 38, will tend to raise the shoulder 57. thereby raising the knife edge 56 and rotating the segment 54 in a clock-wise direction, looking from the rear. This in turn rotates the indicator in a counter clock-wise direction, looking from the rear.

Contact arms 60 and 61, corresponding to the maximum and minimum of temperature at which it is desired to have the indicator act to close a circuit and thereby operate some piece of electrically controlled mechanism, are preferably composed of some conductive material, and are pivoted at a point in alinement with, the axis of the indicator 50. Each of these contact arms comprises a flat ring 62, having an outwardly extending arm 63, twisted as at 64 to form a flat surface at its upper end for the reception of a contact point 65 of platinum or other suitable material. On each of the contact arms, intermediate the outstanding portion 63, is provided a lug 66 of insulating material adapted to engage a corresponding lug on the other contact arm and thereby prevent the contact points of the arms 60 and 61 from touching when brought toward each other.

On each of the contact arms are provided hubs insulated from the arms and comprising two circular washers 67 adapted to em brace between them two sheets of insulating material 68, one of each of these being on either side of the ring portion 62, in the central hole of which a disk of insulating material 69 is shown, through which suitable rivets act to clamp the whole together. The electrical communication with the contact arm 61, is established through a spring brush '71, having a U-shaped end bearing on the edge of the ring 62 and terminating at its other end in an L-shaped support 72, attached to an insulated panel 75, carried by the case 10 and having upwardly extending arms 76, adapted to act as stops for the contact arms to prevent them from being moved in contact with the sides of the case. The panel42 before mentioned, adapted to provide an insulating shield between the contact arms and the plate 41, is secured to these arms 76. The contact arm 60 is provided vith a similar spring brush 70 adapted to engage the edge of its corresponding ring 62. The supports 72 for the contact springs 70 and 71, are provided with suitable communicating terminals extending hrough the front of the case and clamping thereto a suitable bar of insulation 73, and each having means for connection to its respective lead wire. A similar terminal 74 has been provided intermediate these two and adapted to extend through the insulated bars 1 8, 75 and 42, and be electrically connectcd to the plate 41, before mentioned, which through contact with the pivot 51, provides a circuit from the terminal 74 to the indicator 50. It will be seen that a suliicient movement of the indicator in either direction causing it to touch one of the contacts 60 or 61, would complete a circuit.

In order that the range of action of this thermostat may be varied to change the points at which the circuits through a controlling device will be completed, I have provided means for adjusting the position of the contact arms and for retaining them in that position. The hub formed on the ring 62 of the contact arm 61, is rigidly mounted on a shaft 80, which extends for wardlv through the front cover 14 of the case 10, while the corresponding hub formed on the arm 60 is rigidly carried on. the inner end of a tubular sleeve 81 extending forwardly through the casing, surrounding and rotatable independently of the shaft 80. Rigid with this sleeve 81 outside of the front plate, is a knurled knob 82, having a reduced hub portion rigidly carrying a ring 84, provided with a notched periphery.

The outer end of the shaft 80 has an angular portion fitting into an angular opening in a similar knurled knob 83. This knob has a notched ring portion 85 and is preferably secured in place by means of a nut 86 threaded on the end of the shaft 80. It will be seen that by rotating either of the knobs 82 or 83, the corresponding contact arm may be swung for any desired distance.

To provide a suitable friction, retaining either of these arms in position, while adjusting the other, I prefer to provide devices engaging the grooves on the rings 8d and 85, comprising balls 87, held into engagement with the notches by suitable springs 88 carried in bores 89 into which are threaded suitable screws 90. These bores are preferably made in the end portions of a rectangular casing 91, suitably mounted on the front cover 14 of the case 10. As shown, the knurled portion of the knobs is larger in diameter than the width of the housing 91, the knob 83 being outside the housing and edge of the knob 82, projecting through slots in the top and bot tom surface of the housing. This Provides for the knob being readily grasped by the operator when adjusting the contacts. Within the hub of the knob 83, is provided a coil spring tending to separate the knobs 82 and 83, thereby drawing the shaft forwardly while pressing the knob 82 and the sleeve 81 inwardly and holding the two hubs of the contacts in position, after the nut 86 is loosened. This nut 86 may be loosened while moving the contacts, and tightened to permanently fix them in any desired position.

It will be seen that I have provided a thermostat in which the multiplying mech anism, electrical contacts, etc., are so constructed that they may be cheaply manufactured, easily adjusted, and so connected with the thermostat elements that these may be placed in extreme temperatures without affecting the action of the above named parts; that I have provided maximum and minimum contacts which may be adjusted with regard to the indicator and each other by means outside the casing to provide for the use of the device under various conditions; for example, the contacts may limit the movement of the indicator between points separated by amounts varying from 10 Fahrenheit to 300 Fahrenheit, and the range of the device may be from 0 to 300 Fahrenheit.

Having thus described my invention, what I claim is:

1. In a device of the character described, the combination of a case, an indicator pivoted within the case, a pinion carried on said pivot, a gear segment meshing with said pinion comprising an outstanding arm and a knife edge, a multiplying lever pivoted within the case and adapted to bear against said knife edge, a tube exterior of the case having a high co-efliciency of ex pansion, a rod within said tube and insulated therefrom having a comparatively low co-efficiency of expansion, said rod connected to the multiplying lever whereby the movement of the rod is transmitted to the indicator, and a contact within the case whereby the movement of the indicator may complete the circuit.

2. In a device of the character described, the combination with a case, of an indicator therein and a thermostat and connecting mechanism between the thermostat and indicator, a pair of contact arms with which the indicator is adapted to cooperate, a shaft connected with one of the contact arms, a sleeve surrounding the shaft connected with the other contact arm, said sleeve and shaft projecting to the exterior of the case, a housing exterior of the case about the projected sleeve and shaft, a pair of knobs on the sleeve and shaft respectively, and detent mechanism for said knobs carried by said housing.

3. In a device of the character described, the combination of a case, an indicator pivoted within said case, thermostatic means exterior of the case controlling said indicator, a pair of contact arms having insulated hubs, one of said arms mounted on a shaft extending through the side of the case, the other on a sleeve surrounding said shaft and ournaled in the case, a housing exterior of the case surrounding the sleeve and the shaft, a pair of knobs mounted in the housing and carried on the end of the shaft and the sleeve, each of said knobs having a notched hub, and resilient means pressing against said notched hubs for retaining these knobs in their respective positions.

4. In a device of the character described,

the combination of a case, an indicator pivoted within the case, a pinion carried on said pivot, a gear segment meshing with said pinion and having an outstanding arm, a multiplying lever pivoted within the case and adapted to bear against said arm, a tube exterior of the case having a high co-efficiency of expansion, a rod within said tube and insulated therefrom having a comparatively low co-efficiency of expansion, said rod connected to the multiplying lever whereby the movement of the rod is transmitted to the indicator, a pair of contact arms pivoted within the case and insulated therefrom, and means exterior of the case whereby these contacts may be adjusted with regard to the indicator and each other.

5. In a device of the character described, the combination of a case, an indicator pivoted within. the case, a pinion carried on said pivot, a gear segment meshing With said pinion comprising an outstanding arm and a knife edge a multiplying lever 00- operating with the knife edge, a thermostatic means connected with the multiplying lever and adapted to move the same to cause a greater movement of the indicator, and a contact within the case whereby the move ment of the indicator may complete a circuit. 1a

In testimony whereof, I hereunto a'HiX my signature in the presence of two witnesses.

MERLE M. MASON. Witnesses JUSTIN V. MAGKLIN, ARCHER V. RICHARDS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, I). G. 

